You have several options for viewing execution plans. This chapter looks at the options for viewing them graphically and as a result set in Management Studio, as well as viewing them via Dynamic Management Views and capturing them in SQL Server Profiler.
In addition, many of the preceding methods enable an execution plan to be saved as an XML file, which can be opened later using Management Studio.
SQL Server can return the estimated query execution plan before the query is executed, or it can return the actual query execution plan with the results of the query.
The difference between the estimated and the actual typically isn't the plan; the sequence of physical operations are often the same. The difference in the estimated versus actual plans are the number of rows returned by each operator. Before the query is executed, the Query Optimizer can estimate the number of rows for each operator based on statistics and use ...